At Presqu'ile provincial park, roughly 40 km to the south, the brown thrasher is an uncommon migrant and breeding summer visitor, between late April and mid-October (LaForest, 1993, pp.283-284). In Peterborough county, to the northwest, the thrasher is a common summer resident with, remarkably, three winter records (Sadler, 1983, p.125). The brown thrasher is widespread across southern Ontario (Cadman et al., 1987, pp.336-337). More scattered breeding sites extend past Thunder Bay to the Manitoba border. The species is most abundant nowadays from Lake Simcoe east to the St. Lawrence waterway (Cadman et al., 2007, pp.448-449). However, the thrasher is in decline, as favourable scrub habitat in abandoned farming land is reclaimed by forest.
Cadman,MD, Eagles,PFJ and Helleiner,FM (1987) Atlas of the Breeding Birds of Ontario. Federation of Ontario Naturalists and Long Point Bird Observatory, published by University of Waterloo Press, 617pp.
Cadman,MD, Sutherland,DA, Beck,GG, Lepage,D and Couturier,AR (editors) (2007) Atlas of the Breeding Birds of Ontario, 2001-2005. Bird Studies Canada, Environment Canada, Ontario Field Ornithologists, Ontario Ministry of Natural Resources, and Ontario Nature, 706pp.
LaForest,SM (1993) Birds of Presqu'ile Provincial Park. Friends of Presqu'ile Park / Ontario Ministry of Natural Resources, 436pp.
Sadler,D (1983) Our Heritage of Birds: Peterborough County in the Kawarthas. Peterborough Field Naturalists / Orchid Press, Peterborough, ON, 192pp.